San Antonio River Foundation Confluence Park

Water Purification at Confluence Park With the San Antonio River Foundation’s Nature of Art Education Series

Confluence Park is an outdoor learning laboratory situated alongside the San Antonio River and the Mission Reach Ecological Restoration Zone. During the school year, Confluence Park normally serves as a field trip destination, providing hands-on, environmental education for school groups while eliminating all financial barriers, including bus and substitute teacher costs. Since opening in March of 2018, Confluence Park has also hosted Nature of Art, an annual summer camp for kids ages 7–11 in partnership with the Southwest School of Art. Nature of Art focuses on the integration of science and art by providing ecological learning through creative expression.

This year, amidst the COVID-19 pandemic, Nature of Art migrated to a virtual platform with many tweaks and changes to best serve the community while preserving the summer camp feel. Each virtual camp included live videoconferencing with instructors, video chats with science ambassadors, and curated art kits so that each camper would have all the tools necessary to summer camp from home like a pro. Best of all, tuition was waived so that any child could attend (virtually) completely free of charge.

Today, as Park Program Coordinator, I am excited to bring you an at-home learning activity from our Nature of Art education series. Our team is creating these activities to extend learning and bring the San Antonio River to your living room. Each video features a different science ambassador from our Nature of Art summer camp and includes DIY activities and instructions so that anyone who wants to participate can do so from the comfort of their own home—or backyard!

For more information about the San Antonio River Foundation and Confluence Park, please visit our website, To explore more ideas about experiences that you can do while learning at home with your kids, visit the main page, Charter a Voyage of Learning.

Water Purification Using Household Materials

In the video below, Ryan Beltrán of Elequa teaches us about a water purification method known as electrocoagulation. This type of water purification relies on ions released when electricity runs between two submerged electrodes. The ions condense and attract common water pollutants, such as lead or arsenic, and cause them to rise or sink in the water, thus making them much easier to filter out and leaving improved-quality water behind. When you watch this video, you will learn how to assemble your own eco-coagulator kit using materials found at home.

This activity can be adapted for students of different ages from elementary to high school. For more information on making this experiment developmentally appropriate for your budding scientist, visit the Teacher Resources page.

About Elequa

The Make Water program encourages innovation, collaboration, and problem-solving through a STEM-based, hands-on curriculum that addresses real-world water issues. To learn more about Elequa and the Make Water program, visit

The Challenge

Create and test a water purification system out of household materials you find on an indoor scavenger hunt. Since you may not find all the basic materials on your scavenger hunt, the list also contains alternative materials. We challenge you to mix and match these items and share your results (the good, the bad, and the ugly!) Email with the subject “Coagulator Build” to share your observations.

Materials Checklist

• Tap water

• Two clear cups

• Two rubber bands

• Table salt

• Cardboard size 1½” x 4½”

• One 9-volt battery (energy source)

Alternative materials: AA, AAA, C, or D battery and wire to connect to electrodes

• Two screws, 2½” to 4½” long (electrodes)

Alternative materials: nails, aluminum foil, or aluminum can cut into strips the same length

• Acrylic paint (pollutant)

Alternative Materials: Food coloring, watercolor paint

• Two paper coffee filters (filtration)

Alternative Materials: paper towel, napkin, scrap of T-shirt material

Tools Checklist

• Scissors

• Pen

• Spoon or stirring utensil

Safety Note

Although the setup will use very low energy, use caution when working with batteries, especially with water. The electrolysis process that we are utilizing in this activity gives off tiny amounts of oxygen, hydrogen (which is flammable), and chlorine (when salt is used). Please make sure you are in a well-ventilated room and make sure children have adult supervision during these experiments.

Read More About Water Purification and the San Antonio River

Teacher Resources at Make Water

Water Purification From Scavenged Household Items Challenge at Instructables (download as pdf)

• Activity sheet about Benthic Macroinvertebrates from the San Antonio River Foundation

Self-Guided Tour of Confluence Park

San Antonio River Foundation field trip

Local Connection: Confluence Park and the San Antonio River Foundation

At the San Antonio River Foundation, we support scientific and educational activities that promote and encourage the conservation, stewardship, restoration, preservation and enjoyment of the San Antonio River Basin’s land and water resources. Our overall goal is to increase environmental equity and promote stewardship of our San Antonio River. You can find more information on our Nature of Art education series on our website and stay up to date by following our social media channels: Facebook, Instagram, Twitter, and YouTube. Confluence Park is open daily from sunrise to 11 pm. Visit today! 

Donate to the San Antonio River Foundation

As you may know, the end of the year is an important fundraising time for all non-profits, including the San Antonio River Foundation. This critical effort ensures that we can continue our work to provide world-class education programs, unique recreation opportunities, restored habitat and ecology, and one-of-a-kind public art pieces along the San Antonio River. Each of these initiatives bolsters our mission to make the river vibrant, healthy, and accessible to ALL.

We hope you will join us as we work towards our goal of reaching $25,000 by December 31, 2020.

Charter Moms Chats

Watch Frates Seeligson, Executive Director of the San Antonio River Foundation, and Sara Ramirez, Park Program Coordinator, speak with Inga Cotton on Charter Moms Chats about this at-home learning activity and the Nature of Art education series on Monday, December 7, 2020 at 4 PM Central live on Facebook and YouTube.

To explore more ideas about experiences that you can do while learning at home with your kids, visit the main page, Charter a Voyage of Learning. For tips about exploring more trails along San Antonio’s waterways, read “Explore San Antonio’s Greenway Trails System” by Brandon Ross, Parks and Recreation Manager for the City of San Antonio.

About the Author and Guest

Sara Ramirez, Park Program Coordinator for the San Antonio River Foundation, is the author of this blog post. A trailblazing Chicana, Sara’s educational background is a unique blend of science, art, and culture. Sara received a B.S.A. in Biology from the University of Texas at Austin, and is currently pursuing her M.S. in Environmental History from St. Mary’s University. Sara has years of experience in different educational arenas throughout San Antonio and Austin, specializing in nature-based, experiential learning. As an avid eco-adventurer, Sara enjoys hiking, kayaking, and nature walks with her husband and their yellow Lab, Hoppus.

San Antonio River Foundation Executive Director Frates Seeligson also joins us for Charter Moms Chats. Frates graduated from Duke University in 1992. Upon returning to Texas, he studied ranch and range management at Texas Christian University. A fourth-generation rancher, he has managed agricultural operations across South Texas for over two decades, with a specific focus on native habitat management and restoration. In 2007, Frates joined the board of the San Antonio River Foundation. Over these years he actively participated in the San Antonio River Improvements Project. In 2016, Frates joined the staff of the River Foundation as Director of Confluence Park. In this role he managed the fundraising, construction, and programming of Confluence Park, a one-of-a-kind educational venue for environmental education along the banks of the San Antonio River. In July 2019, Frates took over the Executive Director position for the River Foundation. To Frates, the San Antonio River is the cultural and environmental heart of the city, linking the entire city. Its restoration serves as an inspiring example of the importance of preserving our native habitat.


Dec 07 2020


All Day

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